FRACTIONATED REACTION-TIME IN WOMEN AS A FUNCTION OF AGE AND PHYSICAL-ACTIVITY LEVEL

Comparisons between young and older women runners and sedentary contro ls were examined on simple and choice reaction time tasks involving el bow flexion and extension. Reaction time was fractionated into premoto r and contractile components using electromyography. Young runners wer e significantly faster and the older controls were significantly slowe r than all other groups on ail reaction time tasks. The older runners were not significantly different from the young controls in any of the reaction time tasks, thus indicating that a history of running may el iminate or retard the slowing of reaction time that normally accompani es aging. All four groups had similar contractile times, indicating th at the differences in reaction time were attributed to central process ing in the premotor component of reaction time.